Rotating an image in Photoshop and the Distortion patternMarch 15th, 2012 | Posted by in Experiments
I stumbled on an interesting side effect when rotating an image in Photoshop. If an image is rotated enough times, a distortion pattern will appear.
Like just about every other transformation in Photoshop, rotating a layer will alter pixels and disrupt the image in some way. However, I did find that rotating an object 90 or 180 or 270 degrees doesn’t have any effect on the image’s quality. I figure this is because pixels are square and you’re basically just turning them on their sides. Any other degree of rotation will cause pixels to blend with surrounding pixels. To best display this, I created the below 6 pixel by 6 pixel layer and rotated it 90 degrees and 45 degrees. The layer has been enlarged of course for better visibility. You can see that all the pixels of the middle image have bleed into each other when they are rotated at 45 degrees.
To easily apply several rotations, I created a Photoshop action that will rotate an image 15 degrees for a total of twenty-four times so that it does a full 360. If you’re interested in playing around with this action, you can download it here.
Here is the original image scaled up to 480 pixels.
The image has been rotated 1 full 360 which is 24 rotation actions. Small amounts of noise can be seen between each of the lines.
The image has been rotated 10 full 360′s which is 240 rotation actions. Try doing that without an action! The noise is much more pronounced.
The image has been rotated 20 full 360′s which is 480 rotation actions. The noise is forming a pattern at this point.
The image has been rotated 50 full 360′s which is a total of 1,200 rotation actions. The pattern has grown and bleed into each of the stripes. Color shifts appear on the edges.
This rotation distortion has some interesting effects on photos as well. The below image is roughly 250 pixels by 400 pixels. The right image has been rotated 15 degrees for a total of 240 times. The pattern will actually keep parts of the image recognizable. As side note, the higher the resolution, the smaller the lines will be.
That’s about it. I’m not sure why this pattern appears but hey, feel free to post a comment if you know the science behind this effect.